Mesotrione formulations

ABSTRACT

Herbicidal formulations comprising (A) mesotrione (2-[4-methylsulfonyl-2-nitrobenzoyl]-1,3-cyclohexanedione). (B) about 0.3 to about 2.5 percent of crop oil concentrate or about 0.3 to about 2.5 percent of methylated seed oil, on a volume to volume basis, based on the total of (A), (B), (C) and (D). (C) about 0.5 to about 5% of a urea ammonium nitrate on a volume to volume basis, based on the total of (A), (B), (C) and (D), or about 0.5 to 5% based on dry weight, of ammonium sulphate fertilizer, based on the total weight of (A), (B), (C) and (D), and (D) a diluent.

This application claims benefit of Ser. No. 60/231,007 filed Sep. 8,2000 and Ser. No. 60/231,796 filed Sep. 11, 2000.

Mesotrione, (2-[4-methylsulfonyl-2-nitrobenzoyl]-1,3-cyclohexane dione),is a new broadleaf weed herbicide being developed for post emergence andpreemergence use in corn. Adjuvants are highly preferred in order tooptimise its post emergence activity. Glasshouse and field experimentshave been conducted to evaluate weed and crop response to mesotrioneapplied post emergence with several adjuvant systems. Rates ofmesotrione ranged from 50 to 140 g active ingredient (ai) per acre (A).Adjuvant systems tested include;

-   (i) no adjuvant (control),-   (ii) crop oil concentrate (COC),-   (iii) non-ionic surfactant (NIS), and-   (iv) methylated seed oil (MSO),    each with and without urea ammonium nitrate (UAN and ammonium    sulphate (AMS) fertilizers.

The average crop response to mesotrione applied with crop oilconcentrate plus ammonium nitrate or ammonium sulphate at 105 g activeingredient per hectare (ha) is less than 2% with a maximum injury ofless than 10% in over 96% of the experiments.

The use of methylated seed oil with mesotrione increases the potentialfor crop injury. The average crop response to mesotrione applied withMSO plus UAN or AMS at 105 g active ingredient per hectare (ha) was only3%, but injury was greater than 15% in more than 15% of the trials. In aseries of trials where broadleaf weed control was challenged by largedifficult-to-control weeds, mesotrione applied with COC plus UAN or AMSand mesotrione applied with MSO plus UAN or AMS gave similar levels ofcontrol. Mesotrione applied with NIS plus UAN or AMS tended to give lesscontrol than the combinations with COC or MSO. Experiments also showthat varying water quality and application volumes have little or noimpact on the activity of mesotrione when applied at recommended rateswith these adjuvant systems.

Data from these experiments show that in order to optimise weed controland minimize crop response with mesotrione, the preferred adjuvantsystem is COC plus UAN. However, if efficacy with acceptable sacrificein crop damage is the desired result, mesotrione plus MSO and UAN or AMSis the formulation of choice.

Thus, in a first aspect, the present invention provides a herbicidalformulation comprising

-   -   (A) mesotrione        (2-[4-methylsulfonyl-2-nitrobenzoyl]-1,3-cyclohexanedione),    -   (B) about 0.3 to about 2.5 percent of crop oil concentrate or        about 0.3 to about 2.5 percent of methylated seed oil, on a        volume to volume basis, based on the total of (A), (B), (C) and        (D),    -   (C) about 0.5 to about 5% of a urea ammonium nitrate on a volume        to volume basis, based on the total of (A), (B), (C) and (D), or        about 0.5 to 5% based on dry weight, of ammonium sulphate        fertilizer, based on the total weight of (A), (B), (C) and (D),        and    -   (D) a diluent.

Preferably, the mesotrione is utilized in an amount of about 1 ounce (28g) to 6 ounces (170 g) per acre; the amount utilized per 100 (US)gallons (380 liters) of solution would thus correspond to how manygallons of solution would be applied on a per acre basis. Such amountswould ordinarily vary from about 3 ounces (85 g) in 5 gallons (19 l) toabout 3 ounces (85 g) in 30 gallons (114 l). In a typical formulation,based on a 100 gallon (380 l) sample of the formulation, about 3 ounces(85 g) of mesotrione will be utilized for post-emergent use, and about5-6 ounces (142-170 g) for preemergent usage.

The term “crop oil concentrate” is a well known term in the herbicideart and denotes mixtures of petroleum oils and non-ionic surfactants,preferably containing at least about 79% by weight of petroleum oil.There are numerous commercially available crop oil concentrate products,including, for example AGRI-DEX, PENETRATOR, and PENETRATOR PLUS andfrom Helena Chemical Company, HER-BIMAX from UAP, ES CROP OIL PLUS fromGromark, and CROP OIL PLUS, from Wilfarm, (83% parafinic oil, 17%emulsifier surfactant). In addition, U.S. Pat. No. 5,238,604,incorporated herein by reference, describes certain adjuvant systems andcrop oil concentrate products.

Preferred amounts of crop oil concentrate are 0.5 to 2%, most preferablyabout 1% on a volume to volume basis.

Methylated Seed Oil is also commercially available. Examples includeDESTINY from Cenex, methylated seed oil from Loveland, methylated seedoil from Helena Chemical, METH OIL from Riverside, PERSIST fromPrecision, SCOIL from Agsco, SUNDANCE II from Rosens, SUNIT-2 fromAmerican Cyanamid and SUPERB from Wilfarm.

In addition, commercial versions of the methylated seed oil are alsosold as combinations with either UAN or AMS, for example PERSIST PLUSand PERSIST EXTRA from Precision (MSO plus UAN) and DYNE-A-PAK, fromHelena Chemical (MSO plus UAN).

Preferably, the methylated seed oil is utilized in an amount of about0.5 to 2.0 percent, on a volume-to-volume basis with the mesotrione,more preferably about 1 percent.

Preferably, about 1 to 3%, more preferably 1 to 2% of urea ammoniumnitrate fertilizer is used. Preferably about 0.5% to 2% of ammoniumsulphate is used.

The diluent is generally comprised of water. It is also possible to useother additives, for example buffers, to control pH. pH buffersubstances are substances known to the person skilled in the art. A pHbuffer substance is a mixture of a weak acid with a virtually completelydissociated salt of this acid and/or a mixture of a weak base with avirtually completely dissociated salt of this base (see, for example,Rompps Chemie Lexikon (Rompp's Chemical Encyclopedia, 7th edition,volume 5, head word “Buffer”). The pH of the buffer hardly changes onaddition of acids or bases.

Preferred buffer substances in the preferred pH range from about 4 toabout 11 are, for example, buffers which contain the following ions;acetate, phosphate, borate, carbonate, citrate, diethylmalonate,nitrilo-trismethylenephosphate. Zwitterionic buffers, such as, forexample, glycine buffer or 2-(N-morpholino) ethanesulfonic acid (MES)are also suitable. The buffer used generally depends on the pH range,for example phthalate is typically used at a pH range of about 3 toabout 4, acetate is typically used at a pH range of about 4 to about5.5, phosphate is typically used at a pH range of about 5.5 to about 75,and carbonate is typically used at a pH range of about 9 to about 10. ApH buffer acetate system is employed in concentrations such that theconcentration in the formulation is about 0.1 to about 0.3 mol/l,preferentially about 0.15 to about 0.25 mol/l. A pH- buffering acetatesystem is actually built in the ‘Mesotrione/Acetochlor Premix’formulation at the specified molar ranges. For each buffer system themolar range is different and system specific, however, based on thebuffering strength at the working pH range.

Further examples of commercially available buffer agents and adjuvantsinclude, but are not limited to BUFFER PS from Helena, which includesalkyl-p-arylpolyethoxyethanol phosphates and organic phosphoric acid,typically utilized at a concentration of about 0.5 to about 4 pt (about0.24 to 1.9 l) per 100 gal (3801), BUFFER EXTRA STRENGTH from Helena,which includes a blend of alkylarylpolyethoxyethanol phosphates andorganic phosphoric acids, typically utilized at a concentration of about4 oz to about 2 pt (about 0.095 to 0.95 l) per 100 gal (380 l),BUFFERCIDE from Custom Chemicals, which includes phosphoric acid,typically utilized at a concentration of about 1 to about 2 pt (about0.47 to 0.95 l) per 100 gal (380 l), AERODYNE and PENETRATOR PLUS.

The formulations can be applied via the air or ground using knowntechniques, typically 5-30 gallons (19-114 l) per acre (0.4 ha) byground or 1-5 gallons (3.8-19 l) per acre (0.4 ha) by air.

The amounts and proportions of components (B) and (C) above arepreferred embodiments. It is contemplated that a range of about 0.1 to1.0% could be utilized in each case.

In a further aspect of the invention, there is provided a method forcontrolling the growth of undesirable vegetation such as weeds aroundthe locus of a desired plant species such as corn, which comprisesapplying the above formulations to the locus of such vegetation.Examples of undesired vegetation are velvetleaf, redroot pigweed, commonwater hemp, Palmer amaranth, ivyleaf morning-glory, prickly sida, giantragweed, common ragweed common cocklebur, Eastern black nightshade,common lambsquarters, Pennsylvania smartweed, common sunflower,jimsonweed, hemp sesbania, toothed spurge, common purslane, largecrabgrass, yellow foxtail and kochia.

EXAMPLES

A series of trials was conducted to evaluate the effect or adjuvants oncontrol of broadleaf weeds with mesotrione. This series included trialson planted weeds and indigenous weeds. Each trial was designed as arandomised complete block with 3 or more replications. Mesotrione wasapplied at 0.094 lb ai/A (105 g/ha, 3 oz/A,) with MSO and COC at 1% v/vwith and without UAN at 1 to 2.5% v/v and AMS at 8.5 lb/100 gallons(about 1%) spray solution. Thirteen trials were conducted in 1999 inwhich 38 evaluations were made on broadleaved weeds includingvelvetleaf, redroot pigweed, common water hemp, Palmer amaranth, ivyleafmorning-glory, prickly sida, giant ragweed, common ragweed, commoncocklebur, Eastern black nightshade, common lambsquarters, Pennsylvaniasmartweed, common sunflower, jimsonweed, hemp sesbania, toothed spurge,common purslane and kochia The high levels of control observed with alltreatments in 20 out of 38 of these datasets tends to mask adjuvanteffects (see Table 1).

TABLE 1 Effect of adjuvants on broadleaf weed control with mesotrioneTRIAL DATA: H-99-US77-52 “All” Broadleaves, 14-36 DAA, 38 datasets MeanWeed # >90% Control % Consistency Mesotrione 0.094 lb + MSO 73 20Mesotrione 0.094 lb + MSO + UAN 1% 78 21 Mesotrione 0.094 lb + MSO + UAN2.5% 79 23 Mesotrione 0.094 lb + MSO + AMS 82 22 Mesotrione 0.094 lb +COC 75 22 Mesotrione 0.094 lb + COC + UAN 1% 78 19 Mesotrione 0.094 lb +COC + UAN 2.5% 77 21 Mesotrione 0.094 lb + COC + AMS 75 20 Mesotrione0.094 lb + UAN 1% 69 17 Mesotrione 0.094 lb + UAN 2.5% 71 22 Mesotrione0.094 lb + AMS 69 19

All herbicide rates are in pounds of active ingredient per acre (lbai/A). 0.094 lb/A is about 105 g/ha.

Adjuvant rates are 1% MSO, 1% COC, 1 and 2.5% UAN and 8.5 lb/100 gal(about 1%) AMS.

The best demonstration of potential adjuvant effects is to concentrateon trials that were conducted under conditions which were not favourablefor herbicidal activity or on weeds which are difficult to control withmesotrione applied alone. Mesotrione applied with the combination Of COCor MSO plus UAN or AMS gave significantly better weed Control than whenapplied with just COC or MSO (See Table 2).

Adjuvants also impact corn injury. This is best demonstrated by lookingat the frequency of injury observed across a large number of fieldtrials conducted between 1996 and 1999. These trials were all designedas randomised complete blocks with at least 3 replications. Mesotrionewas applied at 0.094 lb ai/A (105 g ai/ha) (3 oz/A) plus 1% v/v COC orMSO with and without UAN at 2.5% v/v or AMS at 8 to 17 lb/100 gallons(about 1-2%). Combinations of COC plus UAN or AMS result in feweroccurrences of crop injury than MSO plus UAN or AMS See Table 3).

TABLE 2 Effect of adjuvants from selected trials (adverse conditions(OH) and Difficult-to-control species (AMBEL and AMBTR)) TRIAL DATA;H-99-US77-52 *OH WI MN IN *OH Common Common Giant Giant VelvetleafRagweed Ragweed Ragweed Ragweed ABUTH AMBEL AMBEL AMBTR AMBTR 28 DAA 28DAA 32 DAA 28 DAA 28 DAA 6-8 leaf, 12-14 leaf, 8-9 leaf, 5 leaf, 9-10leaf, 8-10″ 5.5-7″ 8-9″ 2-6″ 8-11″ Average Mesotrione 0.094 lb + MSO 2727 63 88 92 59 Mesotrione 0.094 lb + 73 80 83 93 99 86 MSO + UAN 1%Mesotrione 0.094 lb + 60 63 89 90 98 80 MSO + UAN 2.5% Mesotrione 0.094lb + 65 65 92 88 98 82 MSO + AMS Mesotrione 0.094 lb + COC 47 57 71 6892 67 Mesotrione 0.094 lb + 70 73 81 83 80 77 COC + UAN 1% Mesotrione0.094 lb + 60 60 91 94 89 79 COC + UAN 2.5% Mesotrione 0.094 lb + 52 5272 80 96 70 COC + AMS Mesotrione 0.094 lb + 23 27 65 72 82 54 UAN 1%Mesotrione 0.094 lb + 23 23 91 77 98 62 UAN 2.5% Mesotrione 0.094 lb +AMS 38 38 85 77 95 67 5% LSDs  9 10 13 13 18 *Drought conditions

All herbicide rates in pounds of active ingredient per acre (lbai/A).

Adjuvant rates are 1% MSO, 1% COC, 1 and 2.5% UAN and 8.5 lb/100 gallon(about 1%) AMS

TABLE 3 Effect of Adjuvant on Frequency of Corn Injury using 0.094 lbai/A (105 g/ha) mesotrione with various adjuvants Frequency Distribution(% of trials in each range) Maximum Injury Observed (as %) Adjuvant mean# trials <5 5-10 10-15 15-20 20-25 25-30 >30 COC 1% 0.6 60 98 2 0 0 0 00 COC 1% + 1.8 101 90 6 3 0 1 0 0 UAN 2.5% COC 1% + 1.6 15 80 20 0 0 0 00 AMS MSO 1% 0.6 29 100 0 0 0 0 0 0 MSO 1% + 3.0 38 76 11 5 8 0 0 0 UAN2.5% MSO 1% + 5.5 25 68 8 4 12 4 4 0 AMSExamples of Preferred Formulations Based on 100 Gallons (379 l) ofFormulated Solution for Typical 10 Gallon (38 l) per acre (0.4 ha)Application

-   -   1. (A) 30 ounces (1 kg) of        (2-[4-methylsulfonyl-2-nitrobenzoyl]-1,3-cyclohexanedione),        -   (B) 1 gallon (3.8 l) of crop oil concentrate,        -   (C) 1.5 gallons (5.7 l) of urea ammonium nitrate, and        -   (D) the balance water    -   2 (A) 30 ounces (1 kg) of        (2-[4-methylsulfonyl-2-nitrobenzoyl]-1,3-cyclohexanedione),        -   (B) 1 gallon (3.8 l) of methylated seed oil,        -   (C) 17 lbs (7.7 Kg) of ammonium sulphate fertilizer, and        -   (D) the balance water    -   3. (A) 30 ounces (1 kg) of        (2-[4-methylsulfonyl-2-nitrobenzoyl]-1,3-cyclohexanedione),        -   (B) 1 gallon (3.8 l) of crop oil concentrate,        -   (C) 1.5 gallons (5.7 l) of urea ammonium nitrate, and        -   (D) the balance water

1. A herbicidal formulation comprising (A) mesotrione(2-[4-methylsulfonyl-2-nitrobenzoyl]-1,3-cyclohexanedione); (B) about0.3 to about 2.5 percent of crop oil concentrate, or about 0.3 to about2.5 percent of methylated seed oil, on a volume to volume basis, basedon the total of (A), (B); (C) and (D), (C) about 0 5 to about 5% of aurea ammonium nitrate on a volume to volume basis, based on the total of(A), (B), (C) and (D), or about 0.5 to 5% based on dry weight, ofammonium sulphate fertilizer, based on the total weight of (A), (B), (C)and (D), and (D) a diluent.
 2. The formulation of claim 1, comprisingabout 0.5 to 2.0% crop oil concentrate.
 3. The formulation of claim 1,comprising about 1% crop oil concentrate.
 4. The formulation of claim 1,comprising about 0.5 to 2.0% methylated seed oil.
 5. The formulation ofclaim 1, comprising about 1% methylated seed oil.
 6. The formulation ofclaim 1, comprising about 1 to 3% urea ammonium nitrate fertilizer. 7.The formulation of claim 1, comprising about 0.5 to 2% ammonium sulphatefertilizer.
 8. A herbicidal formulation, on the basis of a 100 gallonsolution, comprising (A) about 30 ounces of(2-[4-methylsulfonyl-2-nitrobenzoyl]-1,3-cyclohexanedione), (B) about 1gallon of crop oil concentrate or 1 gallon of methylated seed oil or ablend thereof, (C) about 2 5 gallons of a urea ammonium nitrate on avolume to volume basis or about 17 lbs of ammonium sulphate fertilizer,and (D) the balance water.
 9. A method for controlling the growth ofundesired vegetation around the locus of a desired plant, whichcomprises applying the formulation of claim 1 to the locus of saidvegetation.
 10. The method of claim 9 in which the desired plant iscorn.
 11. The method of claim 10, wherein said undesired vegetation isselected form the group comprising velvetleaf, redroot pigweed, commonwaterhemp, Palmer amaranth, ivyleaf morningglory, prickly sida, giantragweed, common ragweed, common cocklebur, Eastern black nightshade,common lambsquarters, Pennsylvania smartweed, common sunflower,jimsonweed, hemp sesbania, toothed spurge, common puslane, largecrabgrass, yellow foxtail and Kochia.